A member of the Refugio Oil Spill Response shoreline cleanup clean-up crew removes oil from a rock near Refugio State Beach in Goleta, California, June 6, 2015. (AFP Photo/US CoastT Guard) / AFP

The owner of the pipeline that shed more than 100,000 gallons of oil along the coast near Santa Barbara, California last month had previously stated in a spill response plan offered to state regulators that a rupture in the line was "extremely unlikely."

Plains All American Pipeline, a Texas-based company, outlined
various preventative measures it had taken to avoid a pipeline
breach, which included a monitoring system that would quickly
warn of a break. The analysis -- included in nearly 1,200 pages
of records filed with California regulators -- was initially
conducted in the mid-1990s, according to The New York Times, though
federal regulators endorsed the plan as late as last year.

“The pipeline and its operation are state-of-the-art,”
stated the analysis, conducted by experts assembled by the
company. “Spills are still possible, though extremely
unlikely.”

The spill response plan was released under California's public
records law, the New York Times reported. Though some sections of
the 24-inch, 10.6-mile pipeline just west of Santa Barbara have
been modified since the analysis, some are now questioning the
validity of the company's claims after a six-inch breach along a
corroded section of pipe dumped crude oil along a nine-mile stretch of
the Pacific Ocean on May 19.

A Plains All American spokeswoman would not comment given an
ongoing federal investigation of the spill.

Kristen Monsell, of the Center for Biological Diversity, called
the spill plan inadequate, pointing out that its list of
endangered species was at least 20 years behind.

“It grossly understates the potential for an oil spill,”
she told the New York Times.

US Senator Barbara Boxer said the response plan and the company's
reaction once the spill was detected are both points that deserve
scrutiny.

“We need to find out if the company lived up to the promises
of its oil spill response plan,” Boxer said in a statement.
“I’m concerned that they may not have moved quickly enough to
detect and report the spill, which could have exacerbated the
environmental damage.”

California Attorney General Kamala Harris' office is in the midst
of its own criminal and civil investigations into the spill. In a
visit to the spill site last week, she said "our
investigation is obviously looking at [Plains All American's]
role and their responsibility," the Los Angeles Times
reported.

The coastline affected by the spill is known as Refugio State
Beach, north of Santa Barbara. A state official said Sunday that 44 percent of 96.5 miles of
impacted coast has been cleared of oil.

The pipeline was completed in 1990. It helps ship crude oil
inland from the ocean to refineries in Texas. Plains All American
bought the line in 1998. The line has had minor breaches in the
past, releasing a combined 1,200 gallons of oil.

The LA Times reported over the weekend that the company
has been responsible for more than a dozen spills that have
felled nearly 2 million gallons of hazardous liquid in the US and
Canada since 2004.

Though the cause of the latest spill has yet to be determined,
federal regulators suspect pipe corrosion. In its spill response
analysis, the company said possibilities of a leak based on
corrosion had been "adequately mitigated."

Just gets me how oil companies always think a leak is
impossible: Firm in CA Oil Spill Called a Rupture ‘Unlikely’
http://t.co/9Tb2Dh6VKR

To help stave off corrosion, the company did use a urethane
coating on the inside of the pipeline while covering it with foam
insulation and an outer protective wrap, the New York Times
reported. In addition, the line was subject to cathodic
protection, which is an electric current that travels through the
pipe to prevent corrosion.

The Federal Pipeline and Hazardous Materials Safety
Administration released documents following the spill that showed
testing in early May had found deep external corrosion in some
areas of the line. The company, however, claimed it did not
receive notice of those test results until after the spill.

Federal regulators said the area near the breach was previously
replaced based on corrosion. More than 80 percent of the
pipeline's wall depth was gone, inspectors found. The company
spent more than $40 million to upgrade more than 10,000 miles of
pipeline following a 2010 settlement with the federal government
based on ten spills that released 273,420 gallons of crude oil in
Kansas, Louisiana, Oklahoma, and Texas.